Fuze



Oct. 20, 1953 Filed Nov. 30, 1945 FIG. I

,J. D. JORDAN FUZE 2 Sheets-Sheet l JAMES 0.

INVENTOR JORDAN ATTORNEY Oct. 20, 1953 Filed NOV. 30, 1945 FIG. 5

FIG. 4

J. D. JORDAN 2 Sheets-Sheet 2 W/ FIG 3 SAFETY DEVICES ND F! G SQUIB INVENTOR JAMES 0. JORDAN ATTORNEY Patented Oct. 20, 1 953 FUZE James D. Jordan, Silver Spring, Md., assignor to the United States of America as represented by the Secretary of the Navy Application November 30, 1945, Serial No. 631,951

5 Claims.

The present invention relates to electromagnetic fuzes of the type adapted to be installed in ordnance missiles and more particularly to quick-acting fuzes of the type employed to cause instantaneous detonation of a projectile on impact with a target.

Representative of this general class of fuzes is that disclosed in United States Patent No. ,858,969 to Herbert Ruhlemann, issued May 17. 1932 and-entitled Electric Fuze for Projectiles. Such fuzes generally comprise: (1) An electromagnetic generator for developing energy; (2) a condenser for storing energy so developed; (3) means for permitting the storage of energy during the time of firing of the projectile until the displacement between the generator elements attains a critical value and for thereafter breaking the circuit between the condenser and genera tor; (4) a firing squib consisting of a thin resistance Wire embedded in a priming composition and adapted to be energized by the discharge current of the condenser to cause detonation of the projectile; (5) inertia-operated means for closing a circuit between firing squib and condenser upon target impact; (6) an expedient for preventing operation of the generator until a predetermined time following the firing of the proiectile.

It is an object of the present invention to provide an improved fuze of this type in which motion of the magnetic member included in the generator is employed upon attainment of a critical displacement from the conductive member to break conductors, thereby to permit the condenser to retain its charge until the target is impacted and also to remove a short circuit from the firing squib thereby to place it in operative condition.

It is also an object of the invention to provide an improved arrangement for performing these functions without necessarily employing switches and other moving contacts.

Another object of the invention to provide an improved means for coupling the condenser to the firing squib to cause instantaneous detonation of the projectile upon impact, a means which is sensitive to mere contact with the target.

Another object of the invention resides in the provision of mechanical safety means for affording protection in handling the fuze before it is armed, coupled with means for releasing the safety means to arm the projectile.

For a better and further understanding of the present invention, together with other objects thereof, reference is made to the accompanying drawings, together with the following specification and the claims appended thereto. In the drawings:

Fig. 1 is a schematic of the circuit included in the preferred embodiment of the present invention illustrated in Fig. 2;

Fig. 2 is an elevational sectional view of a preferred form of base fuze in accordance with the present invention;

Fig. 3 is a modified form of base fuze according to the invention;

Fig. 4 is a form of switch suitable for use in the Fig. 3 embodiment ;,and

Fig. 5 is an elevational sectional view of a projectile and fuze assembly, illustrating the manner in which either of the forms of iuze herein disclosed may be installed in a projectile.

Referring now specifically to Fig. 5, there is illustrated a fuze unit ll, installed in contact with a bursting charge 42 and in the base of an tion and spacers l8 and I9. Slidably fitted to the base of the projectile is a case 2| which contains an appropriate propellant powder charge 22. The conductors have such operation, in conjunction with other fuze components presently to be described, as to cause detonation of the projectile at any desired instant either preceding or substantially at the time of impact of the main body 4 13 of the projectile with a target.

Referring now specifically to 2, it will be ,seen that the fuze unit ll comprises an externally-threaded hollow base block 24, which is adapted to be mounted along the longitudinal axis of the projectile with its interior chamber 25 isolated from the charge-containing projectile chamber.

An externally-threaded steel coil block 25 is fitted into the base block. A portion of the coil block projects from block 24 and an outer shell or barrel 21 is threaded at its open end upon this projecting portion, the opposite end of this barrel being closed.

The steel coil block is fashioned with an annular recess to accommodate a coil member 28. This coil is wound upon a magnetic core 29. Disposed within chamber 25 is a circular permanent magnetic inducing member 3|, normally in contact with core 29, and cooperating with the core and coil to function as an electro-magnetic voltage generator.

For retaining the movable magnet 3| against accidental displacement there are provided a pin rality of detents 33, 34, which may be retracted in any one of three selected modes in order to release the magnetic inducing member. Centrifugal force developed by projectile spin may be used to retract the detents against the force of biasing springs 35, 36. Gas pressure developed within the powder chamber of casing 2| upon firing of the projectile may be used for this purpose, the gas being led through ports 31, 3'3 in the base block. Additionally, the detents may, if desired, be sheared by reason of the displacement of magnet 3|, under setback, before the projectile leaves the gun.

The coil block is fashioned with a reduced, tubular, neck portion 40, forming within barrel 2! a space occupied by an annular paper condenser energy-storage means 4|.

Centrally mounted in neck portion 49 is a firing squib or igniter 42. The firing train is completed through a central charge 43 of lead azide, an additional charge 44 of tetryl, and a tetryl booster charge 45 placed in the integral upper cupped portion 46 of the coil block. A safety gate or barrier 48 is interposed between charges 43 and 44 and is provided with a longitudinal port 49 normally ofiset from the longitudinal axis of the projectile and closed. The gate maintains the unarmed conditions of the projectile until a predetermined time after it leaves the gun. The gate is adapted to slide transversely of the projectile under the effect of centrifugal force de veloped by spin, thereby shearing detent e and aligning port 49 between charges 43 and 44.

The coil block and magnetic member 3| are provided with central openings to receive a con centric-circuit-breaking pin member 50a slidably mounted within the magnetic member. The pin has a head portion 5| against which magnetic member 3| bears, after having moved a predetermined distance with respect to coil 28, thereby to retract the pin. Retraction of the pin causes the breaking of conductors 54 and 55 which are secured in slots in the pin. As will be apparent from an inspection of Fig. 1, the breaking of conductor 54 uncouples condenser 4| from coil 28, effectively disables the generator, and prevents the discharge of stored-energy through the coil. Breaking of conductor 55, which conductor is provided for protectively short-circuiting igniter 42 and preventing accidental burning thereof, removes this short circuit and places the igniter in potentially operative condition. It will also be seen that conductors l6 and I! are normally open circuited, but that when a target is impacted the conductors have such operation as to touch or be placed in circuit and thereby to couple the condenser to the firing squib.

When a projectile containing the above-described fuze is discharged from a gun, the following sequence of events occurs: (1) detents 33, 34, are retracted and magnet 3| moves rearwardly under the force of setback, thereby inducing a voltage in coil 28; (2) this voltage causes energy to be stored in condenser 4|; (3) continued motion of magnetic member 3| causes retraction of pin 50, thereby disconnecting the condenser from the generator and removing the short circuit from the firing squib; (4) centrifugal force causes slide 48 so to move as to align port 49 with charges 43 and 44; (5) upon impact with a '4 target conductors l6 and I! are placed in circuit, so that condenser 4| instantaneously discharges through firing squib 42 and causes rapid detonation of the projectile.

Referring now to Fig. 3, there is illustrated a modified form of base fuze in accordance with the invention and in which a conventional circuit breaker is substituted for the conductorbreaking expedient hereinabove described. Components of this embodiment which are similar in structure and function to the corresponding components of the Figure 1 embodiment have the same reference numerals primed and further description thereof is deemed unnecessary.

The fuze illustrated in Figure 3 differs from the Figure 1 embodiment in two essential respects: (1) 'a circuit breaker 58 having an actuating plunger 59 and so disposed and arranged as to be operated by movement of magnet 5|, is substituted for the expedient reflected in the breaking of conductor 54, and functions upon setback to uncouple coil 28 from condenser 4|; (2) a switch, indicated generally at 6!], is substituted for the expedient involved in effecting contact of conductors l5 and I! by impact, the switch being operative upon impact to couple condenser 4| to firing squib 42.

Reference is made to Fig. 4 in describing the last-mentioned switch. It comprises a thin, flexible copper foil diaphragm 6| disposed between two conductor disks 62, 63, in such manner as to class the circuit therebetween upon target impac The disks are separated by insulating spacers 65, 66, and are individually coupled to conductors l6 and IT. The flexible foil possesses suflicient inherent rigidity to be initially and normally held in the safety position, in contact with disk 62, but out of contact with disk 63.

While there have been shown and described what are presently considered the preferred embodiments of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the true spirit of the invention and it is therefore intended, in the appended claims, to cover all such changes and modifications as fall within the true scope of the invention and without that of the prior art.

I claim:

1. In a fuze for an explosive missile having an inertia-actuated electrical energy generating means, an electrical energy storage means, and an igniter for setting off an explosive charge in response to actuation by said electrical energy, a switch serving to complete a closed circuit between said storage means and said igniter, said switch comprising a first conducting member and a second conducting member, an insulating member interposed between said conducting members at the peripheries thereof, a flexible foil member interposed between said insulating member and said second conducting member and remaining normally out of contact with the said first conducting member, but subject to being thrown into contact with said conducting member when the missile strikes a target.

2. A contact fuze for use in an explosive missile, comprising, an electrical energy generating means actuated by inertial forces during flight of the missile, an electrical energy storage device connected to said generating mean for storing a predetermined amount of energy, an igniter, and a switch connected to said storage device and said igniter, said switch including a first ing member when the missile is subjected to impact.

3. A fuze as recited in claim 2, wherein the surface of the first conducting member facing the second conducting member i provided with projections.

4. A fuze as recited in claim 2, wherein the surfaces of the conducting members facing each other are provided with projections.

5. A switch responsive to impact for use in an explosive missile, comprising, a first conducting member and a second conducting member, an insulating member interposed between said conducting members atthe peripheries thereof, and a flexible foil member interposed between said insulating member and said second conducting member and remaining normally out of contact with the first conducting member but being thrown into contact with said first conducting member when subjected to impact.

JAlVLES D. JORDAN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 384,662 Zalinski June 19, 1888 472,193 Marshall Apr. 5, 1892 1,858,969 Ruhlemann May 17, 1932 FOREIGN PATENTS Number Country Date 91,592 Sweden Feb. 24, 1938 859,363 France June 3, 1940 

